Rotary explosive-engine.



E. Lv. AURANU.

ROTARY EXPLOSIVE ENGINE.

APPLICATION man FEB, 21. 1913.

ll46,515e Patented July 13, 1915.

4 SHEETS-SHEET l.

E. L. AURAND.

ROTARY EXPLOSIVE ENGINE.

APPLICATION man FEB.27.1913.

Patented July 13, 1915.

4 SHEETS-SHEET 2.

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@bro/c1413 E. L. AURAND.

ROTARY EXPLOSIVE ENGINE.

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Patented July 13, 1915.

E. L. AURAND.

RoTARY ExPLoslvl-I ENGINE.

APPLICATION FILED FEB.27-

Prented July 13, 191V.

4 SHEETS-SHEET 4.

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EDWARD L. AURAND, vOIE' DENVER, COLORADO, ASSIGNOR '10 HENRY O. JACKSON, 0F

` DENVER, COLORADO.

. ROTARY EXPLOSIVE-ENGINE.

Specification of Letters Patent.

Patented uly 13, 1915.

Application med February 27,1913. serial No: 751,055.-

T0 all whom it may concern:

Be it known that I, EDWARD L. AURAND, a citizen of the United States, residing in the'city and county of Denver and State of Colorado, have invented certain new and useful Improvements in Rotary Exploslve- Engines; and I do declare the following to be a full, clear, and exact description ofthe invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters and figures of reference marked thereon, which forma part of this specification.

My invention relates to'improvements in rotary explosive engines being more especially intended for use as motors for driving the propellers of flying machines or airships, and to this end my improved construction embodies a small amount of material, comparatively speaking, whereby its weight is reduced to a minimum, while at the same time it is exceedingly efficient as a motor of the class described.

' intervals by the cylinders IVhile my improved engine is particularly designed for use on iiying machines of the heavier-than-air class, it is evident that it may be employed in connection with dirigible airships and also as a-rotary motor of general application lor use.

In my improved construction, the crank case proper is in the form of a drum. Upon the periphery of the latter is mounted a hollow annular member interrupted at regular of the motor. In-

. duction ports are located in those portions of the cylinders which are inclosed by the said annular member of the case, while the eilrlhaust ports open directly to the atmosp ere.

Another feature of novelty consists in the special construction for the introduction of the explosive mixture to the inner compartment r chamber' of the crank case through one member or extremity of the crank shaft, in which is located a longitudinally adjustable valve so constructed as to coperate with ports in the crank shaft, whereby the explosive mixture is first passed into a chamber of a blower or pump and thence returned to the crank shaft through similar ports on the opposite side of the longitudinally adjustable valve or on the crank case side of the valve whence the explosive mixture passes directly to the inner compartment of the crank case. This special construction makes it practicable to so adjust the valve in the hollow portion of the crank shaft as to automatically regulate the pressure in the crank case in order to guard 'against the vexcessive pressure within the said case. VA

pressure gageattachment is connected with the valve located in the hollow portion of the crank shaft whereby the pressure within the crank case may be conspicuously indicated at all times.

Having briefly outlined my improved construction, I will proceed to describe the Sallie in detail, reference being made to the accompanying drawing in which is illustrated an embodiment thereof.

In this drawing, Figure 1, is a sectional view of my improved engine taken circumferentially through the'crank case and cutting the crank pin of the )itmen transversely. In this view one-hal of thecrank case is removed and one of the cylinders is shown in longitudinal section. Fig. 2, is a sectional detail view of the hollow intake portion of the crank shaft illustrating the special valve construction and means for indicating the pressure of the explosive mixture'within the crank case. Fig. 3, is a sectional view showing the crank case-cut at right angles to Fig. 1, two of the cylinders 4being shown in elevation. Fig. 4, is a frag mentary sectional view of the outer portion of the crank case being a section taken on the line 1-4, Fig. 1, but on a larger scale. Fig. 5, is a fragmentary view of the crank case viewed from the inside and illustrating the groove for receiving the collar on the cylinder. Fig. 6, is a section taken on` the line 6 6, Fig. 1, cutting one of the filtering devices, the parts being shown on a larger scale. Fig. 7, is a transverse section taken through a filtering device on the line 7-7, Fig. 6. Fig. 8, is a section taken on the line 8-8, Fig. 1, and showing the blower or rotary pump in section all of the parts be ing shown on a larger scale. F ig. 9. is a cross section taken through one of the cylinders on the line 9 4), Fig. 1, shown on a larger scale.. Fig. 10, is a section taken through 'the pump or blower on the line 10-10, Fig. 8. Fig. 11, is a view taken on the line 11-11, Fig. 8.

case which is composed of two-members, 6 and 7, which are' supported by a rotating stub shaft 8 and a hollow fixed crank shaft 9. The two members of this crank case are grooved as shown at 10, to receive ribs or collars 12, formed onthe cylinders whereby-the latter are securely lockedwithin thev crank case when the two members of the latter are connected by bolts 13, which are passed through registering openings formed tering members 16, through which the ex-v plosive mixture passes from the inner compartment of the crank case to the outer compartment 15, thereof, just prior to the passage of the explosive mixture to the cylinders through the intake ports 17, which are in communication with the crank chamber compartment 15, as heretofore explained. An important object of these filtering members is to increase the surface area exposed to contact with the explosive mixture, to such an extent as to prevent so called back firing. Still another function is the breaking' up of the explosive mixture, or finely dividing the same, whereby its volatile character is enhanced and its activity facilitated. These filtering members may be of any suitable construction that may be adapted to roperly perform the aforesaid function. owever, as illustrated in the drawing, each filter member consists of al box-like structure grooved on opposite sides to receive lugs or relatively short inwardly projecting parts 18, formed on the respective members of the crank case whereby the filtering members are locked securely in place. l/Vithin the shell or four outer walls of this box-like device is located a number of separated plates 19between which are interposed corrugated members 20, forming a relatively extensive surface area which is exposed to contact with the"'explosive mixture whereby back firing is prevented. These parts 19 and 20, rranged in the relation stated form a soi of mesh or intricate structure soA interwoven and connected as to finely divide the explosive mixture, or semigaseous substance, i as it leaves the .inner compartment of the crank case on itsway to the outer compartment thereof, and whence it passes directly to the cylinders for explosive purposes.` Beyond the reinforced parts 21, of the 'crank case, in which are formed the grooves l0, for receiving the ribs or collars of the cylinders, the crank case is reduced in thickness, whereby the portions of the cylinders 22, which extend beyond the portions 21, of the case, are exposed on two opposite sides as best illustrated in Fig. 9, of the drawing. These exposed portions of the cylinders contain ports 23, which serve for the exhaust of the burnt gases or products of combustion as the pistons approach their inward limit of movement following the explosions in the outer extremities of the cylinders. thus be apparent that while the exhaust ports 23, are at all times open to the atmosphere, the intake ports 17 are at all times protected by the crank case and in direct communication with the compartment 15, thereof, the last named compartment being in communication with the inner compartment 14, by way of the filtering members 16, as heretofore explained. In order that the crank 'case members may be properly joined or made gasr tight, oneof these members is provided at the periphery of the case and between the cylinders with tongues 24, entering grooves 25, formed in the adjacent member. lllithin each of these cylin-l ders 22, is located a piston 26, which is connected by means of a p itman 27, with a bearing 28, of the crank pin 29. The outer extremity of each ofthese pistonsH is provided with two projections 30, which extend toward the outer extremity of the cylinder 'and are located inwardly beyond the wall of the cylinder, whereby spaces 31, are left between the wall of the cylinder and the said projections, the latter being arranged adjacent the opposite sides of the cylinder where the intake ports 17, are located, whereby as the outer extremity of the piston passes inwardly far enough to uncover the intake ports 17, the explosive mixture will enter the cylinder through said ports and, coming in contact with the projections 30, the latter will constitute deflectors whereby, the said mixture will be deiected or guided outwardly toward the `outer extremity of the cylinder, thus protecting the fresh explosive mixture from contact or intermingling with the burnt `gases or products of combustion as the latter are being removed through the exhaust ports during the scavenging of the cylinders as heretofore explained.

The inner extremity .of each pitman 27, is connected with the bearing 28, of the crank pin 29, by means of an auxiliary pin 32, the said pins for all the pitmen being annularly arranged around the crank pin 29, and connected with the bearing 28, in such al manner that as the crank case rotates in response to the action of the explosions in the various cylinders, the stems 32, will travel in an orbit around the crank pin 29, and permit the pitmen to be reciprocated Awithin the cylinders during the regular performance of theirfunction. The stems 32, are passed centrally through sleeves 33,

which pass through openings 34, in the inner 1.30

extremities of the pitmen 27. The extremitieso these sleeves extend beyond the opposite sides of the pitmen extremities and enter openings35, formed in a sort of spool 36, 4annularly arranged around the crank pin.

i The stems 32, are secured in place centrally given direction to the spool.

' to the body of the crank having coperating grooves Within the sleeves 34, bymeans of nuts 37, secured .upon the threaded extremities of the stems and fitting closely within the adj a'.- cent` extremities of the sleeves 33. The outer extremities of the nuts 37, are flanged to overlap the extremities of the sleeves, ajnd these flanges also occupy recesses or counterbores, formed in the spool.36. All of the pitmen 27, are connected with the spool in the manner just explained, except one which is rigidily secured to the spool as shown at 38, thus giving a positive rotary action in a The body of the crank pin 29, is providedl with a. .sort of disk 39, at one extremity which is formed integral therewith, the said disk extending annularly beyond the body of the crank pin and being recessed, as shown at 40, to receive bearing rings 41, and 42, between which are interposed bearing balls 43, the two rings forming raceways for the balls. The ring 42, is fast on the spool 36, and the two rings 4l and v42, are interposed between an outer annular ange 44, formed `on the disk 39, and an inner annular ange l45, formed on the spool 36. However, the spool bybrazing or otherwise, it is substantially -a part thereof.

A hollow crank pin member 46, isapplied pin at the opposite end from the disk 39, this hollow member 46, having a cone shaped opening, to receive ,the body of the crank pin which is of counterpart' shape. The member 46, is so constructed that when 'applied to the body of' the crank pin, the latter, whenv the member 46 is considered a part thereof, is exteriorly cylindrical in shape. This member r46, is

' also provided with an integral disk 47,

which extends outwardly beyond `the body of the member 46, the outwardly extending portion being recessed as shown at 48, to

receive bearing rings 49 and 50, which are substantially identical with the rings 41 and 42, and perform the same function in the mechanism. The two rings, 49 and 50, are interposed between an annular flange 51, with which the disk 47, is provided, and an annular lange 52, vwith which the spool 36 is provided. The Hange 52, is identical in construction with the part 45, at the opposite end of the spool. The ring 50, is secured to the spool and forms a part thereof in the same manner as the ring 42 is connected with the spool, and bearing balls 53 are interposed .between the two rings 49 and 50. It will be understood that the rings 41 and 49, are fastened in the disks 39 and 47, re-

as thel ring 42, is secured to spectively. The hollow crank pin member 46, is counterbored as `shown at 54, toreceive a nut 55, which is threaded upon the reduced extremity 56,-of the body of the crank pin, whereby the said body of the pin and the hollow member 46, are connected in operative relation and locked together to form a substantially integral device.`

The body of the crank pin and the disk 39, as illustrated in the drawing are formed integral with the hollow member 9, of the crank shaft, while the disk. 47, is formedv understood that when the engine is 1n use the crank case will rotatel on the ball bearings 67, while the crank shaft member 9, remains stationary. During the rotary action .of the 'crank case the inner extremities of the pitmen travel 'around the crank pin whose axis is sulliciently offset from the axis of the crank case to give the pistons the necessary reciprocating movement Within their respective cylinders. The spool 36, which is p carried varound the crank pin with the inner extremities of the pitmen, fits loosely around the outer member 46, of the crank pin, and does not touch the latter. Hence, the bearing of the spool and its rings 50 and 42, is upon the bearing balls 43 and 53, and consequently the thrust due to the explosion within a cylinder located directly above the crank pin is upon the lowest parts of the bearing rings 41 and 49, which are so low as to be almost in line with the axis of the crank case, thusglargely relieving the machine from the tendency of the thrust which, were the bearing pin higher up, would make it much more difficult to properly secure the engine upon a stationary frame work of a iying machine or other structure upon which it is used. J

Attention is called to the fact tha- Tt my improved rotary engine is of the two-cycle type and consequently there. is anexplosion in each cylinder during each reciprocation or back and forth movement of its piston and whereby it results that the volume or mass of the pistons within the crank case is always the same, and consequently there is no compression of the explosive mixture Within the crank case due to the action of the pistons. However, in order to produce the necessary pressure `upon the explosive mixture within the crank case in order to force said mixture intothe cylinders when the induction ports are open, other means must be resorted to. I have therefore, at-

tached to the engine structure as heretofore described, a blower which is designatedin its entirety 'by the numeral 76. This blower consists of a stationary blower casing 77, eccentrically mounted upon and secured to the member 9, of the crank shaft. As illustrated in the drawing this stationary casing 77, is provided with a sleeve 7 8, in direct engagement with the crank shaft member 9, the said sleeve being provided with slots or elongated openings 81, registering with slots 79, formed in the crank shaft member, whereby the explosive mixture as it enters the crank shaft member from the carburetor (not shown) through a pipe 80, is caused to pass into a compartment 82, formed in a stationary structure 96, and in which is formed a partition 81, separating the compartment 82 from a compartment 83, the outer shell of the structure 96, being annularly arranged around the crank shaft member 9. The compartment 82, communicates with a chamber 85, eccentrically arranged around the crank shaft member 9, byan opening 86, while the compartment 83 communicates withthe said eccentrically arranged chamber by an opening'87. f

Annularly arranged around vthe structure96, is a drum 88, upon which are hinged (as shown at 89) a. number of curved blades.

\ or wings 90, which during the rotation of the drum 88, travel in the eccentrically arranged chamber 85, inclosed by a casing 92, which is rotatably movable within the outer stationary casing 7 7, of the blower, the two casings 7 and 92, being equipped with bearing rings 93 and 94 respectively, between which are interposed bearing balls 95. At the `upper extremity of this chamber, the wings are closely folded against the carrying drum 88, as during this folding operation, vthe explosive mixture is forced from theeccentric chamber 85, into the compartment 83,v of the annular structure 96. The

drum 88, is provided with openings 97, through which "the explosive mixture passes from the compartment 82, into the eccentric chamber 85, and from the latterto the compartment 83, the said mixture in entering the compartment 83, also passing through. an opening 87, within the stationary structure 96. By virtue of the operation heretofore described, the explosive mixture enters the compartment 83,under pressure, and is forced therefrom through elongated openings 98, into the hollow portion of the crank shaft member 9, and thence into the crank case through the open extremity 99, of the said crank shaft member.

The drum 88 is caused to rotate with the crank case and the cylinders, by virtue of the fact thatthe'said drum is secured to the said case by fastening screws 100, which are passed through engaging flanges formed on the connected parts, (see Fig. 8). The drum 88, extends beyond the rotary casing 92, inV

the direction of the crank case, and its flange 101 is formed on this protruding part, the last named flange being connected with the flange 102, ofthe crank case, by means of the screws 100, as `heretofore explained.

This protruding part of the drum 88 is surrounded by a relatively wide collar 103, which is interiorly grooved to receive packing 104, whereby a fluid tight joint is formed between the drum and` this collar, the( latter being secured to the stationary casing member,77, of the blower by means of screws 105, passing through a flange 106, which is eccentrically arranged with reference to the axis of the stationary v crank shaft member 9, to coincide in area with one of the ends of the stationary member 77, of the blower, the said -iange 106, in fact closing the eccentric chamber 85 of the blower atv'one end thereof. The casing 92 of the said casing whereby the latter is carried along with the drum, ball bearings being interposed between the casing 92 and the outer stationary casing 7 7 as heretofore.

described. By virtue o'fthis fact the friction between the blades orwings 90 and the casing 92 is practically overcome as the cas- Qing and wings move together.

In order to regulate the introduction of the explosive mixture to the crank chamber through the medium of the blower constructedasheretofore explained, a valve 107 is located within-the hollow crank shaft member 9, the said valve forming a stop or plug whereby the explosive mixture, as it enters the outer extremity of the crank shaft member 9, is caused topass through the slots 81 and 79, formed in the shaft, and sleeves 78, respectively, and thence through the blower and through the openings 98, of the crank shaft, back into the latter, and thence into the crank chamber, on the opposite side of the valve 107, from which it entered the crank shaft member 9. This valve 107,.is reducedv in diameter intermediate its extremities as shown at 108, this reduced part being of sufficient length to place the adjacent extremities of the openings 81 and 98, of the crank shaft member 9, in communication with each other and when the valve is so adjusted, it allows a portion pf the explosive mixture to pass from the compartment 83, to the compartment 82, of the stationary structure 96. By virtue of this feature it becomes practicable to vary the pressure in the crank chamber. Hence, if the pressure within the crank chamber is too great, the valve 107, is adjusted, as shown in Fig. 8, whereby the space 110, due' to the reduction in diameter of the valve 107, between its extremities, is placed in communication with both sets of slots or elongated openings 81 and 98. thus allowing a portion of the explosive mixture .which has been forced into the compartment 83, of the structure 96, to return from the compartment 83, to the compartment 82, through the medium of the space 110, between the extremities of the valve 107. lVhen, however, it is not desired toreduce the pressure in the crank chamber, the valve 107, is so adjusted as to place its extremity in the direction of the crank case far enough in the opposite direction, to cut off the passage of Huid from the openings 98, to the openings 81, of the crank shaft member 9.

In order to accurately measure the pressure of the explosive mixture within the -crank chamber, the valve 107, is provided with a longitudinal perforation 112 which is in communication with a pipe 113, leading to a pressure gage 114. This pressure gage is supported upon the rigid outer extremity 115, of the said pipe. This pipe is threaded as shown at 116, and passes through aA stuffing box gland 117, which is threaded into a nipple 118, formed on an elbow 119, which connects the outer `extremity of the crank shaft member 9, with a pipe 80, leading from a carbureter (not shown). Outside of the gland 117, a nut 120, is screwed on the threaded part 116 of the pipe 113. This nut. is in engagement withrthe outer extremity of the stuiiing box gland and when it is desired to move the valve 107, toward the left, referring to Figs. 2 and 8, the nut 120, is turned in the proper direction to move the pipe 113, toward the left, the valve in this` event acting to compress a spiral spring 121, located within the crank shaft member 9, and surrounding the pipe 113, the opposite extremities of this spring being engaged by the valve 107, and a shoulder 122 formed by reinforcing the elbow 119 interiorly.- In order to move the valve 107 in the opposite direction, it is only necessary to reverse the movement of the nut 120, whereby the t'ension of the spring 121, will act on the valve to move the latter toward the right, (see Fig. 2) as fast as the turning of the nut 120 will permit.

The generator 123, for furnishing the current to supply the cylinders with the spark for explosion purposes, is mounted on an upward extension 124, of the stationary members 78, of the blower, the same being secured thereto by bolts or ca screws 125. A shaft 126, passing throng ihe generator, is journaled in boxes 127, mounted on the blower casing. This shaft 126, extends beyond the box 127, nearer the engine, and uponv this protruding` vextremity is mounted a gear 128, meshing with a relatively larger gear 129, formed on the crank case. Hence,

.be started vouter extremity as the crank case rotates with the cylinders, the gear 128, is operated, and the shaft 126, rotated, whereby the current is generated for the purpose stated. There is a suitable connection from the generator by means of a conductor 139, and binding tact pin 131, contacts 132, carried by the crank case and suitably spaced, conductors 133, binding posts 134, and spark plugs 135, whereby the sparks at the inner extremities of the spark plugs are produced at intervals properly timed for producing the explosions within the outer extremities of the cylinders. As this feature cannot be claimed in its application it will not be necessary to describe the same more in detail.

From the foregoing description the use and operation of my improved engine will be readily understood.

Assuming that the parts are assembled as illustrated in the drawing, the engine may by priming the cylinders or in any suitable manner. As soon as the engine starts, the cylinders and the crank case rotate together upon the axes of vthe crank shaft member 9, and the bearing of the stub shaft 8, which axes are in alinement as heretofore described. During this rotary action of the crank case and cylinders, the reciprocating movement is imparted to the cylinder pistons 26, by virtue of the fact that their inner extremities are connected with the spool 36, annularly'arranged with reference to the crank pin, which is offset from the axis of the crank case sufficiently to give the pistons the desired length of stroke, the crank pin being stationary with the hollow crank shaft member 9. lAs soon as the engine is started the explosive mixture is drawn into the compartment 82, of the stationary structure 96, of the blower, whence it passes to the eccentric chamber 91, where it is acted on by the blades 90, and finally forced into the compartment 83, of the structure 96, whence it passes to the hollow crank shaft member 9, on the'opposite side of the valve 107, from which it entered the said shaft. In this way the crank chamber is keptv supplied with explosive mixture under the necessary pressure. This explosive mixture first enters the inner compartment 14, of the crank chamber and Y passes therefrom through the filter members 16, into the --chamber 15, whence it passes through the induction ports 17, into the cylinders, as fast as the pistons are Withdrawn sufficiently to permit such entrance of the explosive mixture to the cylinders between the pistons and the outer extremities of the cylinders. As soon as the explosive mixture enters a cylinder, the piston begins its outward stroke compressing the mixture in the of the cylinder, and when the piston has reached its outward limit of movement whereby the maximum or apposts 130, a conproximately the maximum pressure is given to the explosive mixture the spark is produced and the explosion follows, driving the piston inwardly and uncovering the exhaust ports 23, through which the burnt gases or products of combustion exhaust simultaneously with the entrance of the explosive mixture to thecylinders, the mixing of the products of combustion and the rich explosive mixture being prevented by the deflectors 30, with which the piston is provided, as heretofore explained.

I claim as my invention:

1. In an explosive engine the combination with a crank shaft of a crank case, cylinders secured thereto, pistons in the cylin.

ders having pitmen connected with the crank pin, the inner extremities of the cylinders being inclosed by the crank case whose transverse depth beyond the inclosed extremities of the cylinders is reduced to expose segments of the cylinders, the said exposed portions of the cylinders being provided with exhaust ports, while the portions of the cylinders inclosed by the outer reduced portion of the crank case, are provided with induction ports in communication with the crank case.

2. In an explosive engine the combination of a crank case whose outer portion is of less transverse depth than its inner portion, cylinders whose inner/extremities are inclosed by thc crank case and whose outer portions beyond the inclosed portions have segments exposed by reason of the reduced transverse depth of the outer portion of the case, theexposed portions of the cylinders having exhaust ports and the cylinders having induction ports in communication with the crank case and mea-ns for supplying the crank case with explosive mixture under pressure.

3. In-an explosive engine the combination of a crank case having inner and outer compartments of varying transverse depth, cylinders whose inner lextremities are inclosed within the inner compartment whose walls fit closely around the cylinders, the partition separating the compartments between the cylinders having openings to allow explosive mixture to pass from the inner to the outer compartment, the outer compartment being in communication with theV cylinders by induction ports formed in the latter, the portions of the cylinders exposed to the atmosphere being provided with exhaust ports.

4. In an explosive engine the combination of a crank case having inner and outer compartments of varying transverse depth, cylinders whose inner extremities are inclosed within the inner compartment Whose walls fit closely around the cylinders, the partition separating the compartments between the cylinders having openings toallow, ex-

plosive mixture to pass from the inner to the outer compartment, the outer compartment being 1n communication with the cylinders -by induction ports, portions of the cylinders axis of the shaft, the crank case having inner and outer compartments of unequal transverse depth, the depth of the outer compartment being less than that of the inner coml partment, cylinders Whose innerextremities areconcealed within the deeper compart- Yment of the crank case, the cylinders being of greater diameter than the transverse depth ofthe outer compartment of the crank case, whereby segments of the cylinder Walls are exposed while portions at-approximately the same distance from the shaft are inclosed, the inclosed portions having induction ports and the exposed portionsexhaust ports, substantially as described.

6. In an explosive engine the combination with a crank shaft having a crank pin suitably ofset from the axis of the shaft, a crank case inclosing the crank pin, cylinders whose inner extremities are inclosed within the crank case which its closely therearound, the crank case having inner and outer compartments, the outer compartment being of ess transverse depth than the inner compartment, the diameter of the cylinders being greater than the transverse depth of the outer compartment whereby portions of the cylinders on two opposite sides are exposed while portions on two other sides are inclosed within the outer compartment, the exposed portions of the cylinders being provided with exhaust ports and the inclosed portions within the zones being provided with induction ports whereby the cylinders are in communication with the outer compartment of the crank case, the partition between the inner and outer compartments between the cylinders lbeing' provided with openings for the passage of explosive mixture to the outer compartment, and means for supplying the explosive mixture to the inner compartment of the crank case under pressure, substantially as described.

7. The combination with a crank shaft having a crank pin suitably ofset from the axis of the shaft, cylinders, a crank case completely inclosing the inner extremities of the cylinders and having an outer portion of less transverse depth t an the diameter of the cylinders, whereby parts of the cylinders are exposed and other portions covered in the zone of the reduced portion of the crank case, the said exposed portions of the cylinders having exhaust ports and the said covered portions induction ports, substantially as described.

8. The combination with a crank shaft having a crank pin suitably offset from the axis of the shaft, a crank case completely inclosing the inner extremities of the cylinders and having an outer portion of less transverse depth'than the diameter of the cylinders, whereby parts of the cylinders are exposed and other parts covered in the zone of the reduced portion of the crank case, the said exposed portions of the cylinders having exhaust ports and the said covered portions induction ports, the crank case having openings between the cylinders through which the explosive mixture passes to the induction ports of the cylinders.

9. The combination with a crank shaft having'a crank pin suitably ofset from the axis of the shaft, a crank case inclosing the crank pin, cylinders whose inner extremities are inclosed by the crank case, the said case having an inner compartment in which the inclosed extremities of the cylinders are 1ocated, the said case also having an outer compartment of less transverse depth than the inner compartment, the transverse depth of the outer compartment being less than the diameter of the cylinders, whereby portions of the cylinders upon opposite sides areexposed in the zone of the outer compartment of the case, while other portions in the same zone are covered, the exposed portions havvwith each other, and lter members located in said openings for the purpose set forth.

10. The lcombination with a crank shaft of a crank case having inner and outer compartments, cylinders entering the crank case Vand passing through .the two compartments,

the cylinders having induction ports in communication with the`outer compartment, and filter members located in openings formed in the partition between the two compartments through which the explosive mixture passes to supply the cylinders, substantially as described.

11. In an explosive engine, the combination of a crank shaft, a crank case having inner and outer compartments, cylinders passing through said compartments, the partition separating the compartments having openings between the cylinders, whereby the two compartments are placed in communication. with each other and iltering members for the explosive mixture, removably mounted in said openings, the cylinders having induction ports in connection with the outer compartment of the crank case, substantially as described.

ln testimony whereof I aiix my signature in presence of two witnesses.

EDWARD L. AURAND. 

